Microfluidic systems manipulate microliter and smaller scale volumes of fluids. Ink-jet printing and biochemical assays are two prominent applications of microfluidics among many others. The ability to move, control and mix tiny quantities of liquids is valuable in biochemistry since it permits more experiments to be done with a given amount of starting material. The increased surface-to-volume ratio associated with microfluidic channels as compared to traditional microwell plates also speeds up surface reactions upon which some kinds of assays are based.
Despite the profound advances in microfluidics achieved over the last 30 years, there is room for improvement. It is still a challenge, for example to make microfluidic valves that open and shut as reliably as conventional size valves. New approaches to interfaces between microfluidic devices and microwell plates are needed. Finally, microfluidic assays need to be made scalable so that hundreds or thousands of assays can be performed in parallel on one chip.